Do you mean more than one game, instead of profile? One profile = one gamertag.
I think I know what you are talking about. Recently, when Live updated their dashboard system, all of my DLC for BOTH Oblivion and FO3 became inaccessible, as in not there. And yet, when I navigate to the system, they are there...... So I reinstalled the DLC, and it seems like the new Dashboard just wanted me to "re-point" to the DLC. Make sense? I reinstalled, without deleting (reinstalled right over the previous installment) and when back to my games, and all my stuff was there, in both games. And I haven't had a problem since.
I am not connected to Live, but I check in for updates.